1. Field of the Invention
The present invention relates to a muffler structure for an engine disposed on a rear portion of a vehicle, particularly a lawn mower.
2. Description of the Related Art
A lawn mower, as disclosed in U.S. Pat. No. 5,029,668, for example, has a muffler disposed in front of and below an engine to direct exhaust gas obliquely downwardly in order to avoid withering or burning of lawn by exhaust heat from the muffler. This known muffler system further includes a cooling fan having a vertical rotary shaft and disposed above the engine to cause cooling air to flow downwardly. A cooling air guide curved along a lower surface of the muffler is required for deflecting the cooling air flows.
In a muffler system as disclosed in the Japanese patent application laid open under No. 1990-293330, a muffler is disposed adjacent the center of a front wall of an engine, and an exhaust pipe extends downwardly from the muffler and bent to a lateral position to open in a transverse direction of a vehicle body.
In these conventional muffler systems, the muffler has an exhaust outlet not directly pointing to the ground to avoid adverse influences on lawn of the exhaust heat from the muffler. However, since the exhaust outlet is located forwardly of a driver's seat with respect to a moving direction of the vehicle, the exhaust gas from the exhaust outlet is not positively prevented from reaching the driver.
Further, since the opening direction of the exhaust outlet is a primary consideration, the muffler is not sufficiently cooled by air flows generated by the cooling fan, or an additional guide duct is necessary for guiding the air flows to achieve sufficient cooling.